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— Plains and silvery minnows: These two small minnows are very similar in appearance <br />and historically common to abundant in preferred habitats in the central U.S. (Page and <br />Burr 1991). Both minnows have been listed by Missouri as endangered, and species of <br />concern in Kansas. Formerly abundant species in the upper Missouri River, both of <br />these minnows have undergone a "drastic" decline and are anticipated to become <br />extirpated if this trend continues (Pflieger 1997). Hesse (1994) reported the catch/effort <br />of plains /silvery minnow decreased in the Nebraska portion of the Missouri River by 96% <br />from 1971 -1993. The fish has been extirpated from Arkansas (Robison and Buchanan <br />1988) <br />The plains minnow is ecologically separated from its close relative by habitat <br />preference: it prefers river channels with sandy substrate, while the western silvery <br />minnow prefers protected areas with a silt bottom. Decline of these small fishes in <br />altered environments is likely due to competition and predation by introduced and native <br />fishes. <br />— Speckled chub: This intermediate -sized (to 3 in) barbeled minnow has a long bulbous <br />mouth and small black spots on sides and back (Page and Burr 1991). It is listed as a <br />species of concern by Kansas. Population shifts have recently occurred in this species, <br />and it has decreased in numbers in the upper Missouri and Mississippi rivers (Pflieger <br />1997). Hesse (1994) documented a 77% decline in catch/effort in the Missouri River in <br />Nebraska from 1971 -1993. Little is known about its life history needs, but its progressive <br />decline in upstream areas that are affected by reservoirs is suggestive of the loss of <br />important habitats or nonnative fish interactions. <br />—Silver chub: This large (to 9 in) barbeled minnow has a large eye and bright silver - <br />white sides(Page and Burr 1991). It has been listed as endangered in Missouri, a <br />species of concern in North Dakota, and a peripheral species in South Dakota (Power <br />and Ryckman 1998). Historically, this was one of the most common minnows of the <br />Missouri, Mississippi, and large prairie rivers, however, populations have declined <br />(Pflieger 1997). Hesse (1994) reported that catch/effort of silver chub declined 70% <br />from 1971 to 1993. Information about this fish is scant, but it seems to have declined <br />most rapidly in prairie regions that have been the most affected by reservoir <br />construction. Because this fish evidently does well in quiet habitats of large streams but <br />it evidently does not do well in reservoir habitats, which is suggestive of adverse <br />interactions with reservoir fishes. <br />— Paddlefish: The paddlefish is one of the largest freshwater fish in North America, and <br />is represented by two extant species that are relicts of an ancient line of fishes, one in <br />the Mississippi- Missouri river system and one in the Yangtse River of China. This shark- <br />like fish with an elongated, paddle -like snout averages about 60 lb, but can reach sizes <br />of over 160 lb and over 6 feet (Pflieger 1996). A commercially important species, <br />catches of about 2.5 million pounds were reported prior to 1900, but the fish has <br />declined, and catches seldom exceed 16,000 pounds (Pflieger 1997). <br />26 <br />